A lot of micros are placed in my area. I like them because they are typically more difficult to find. I also place a lot of them. We use bison tubes for the caches, they're small and water proof. The regular size are more fun for my children (and I like them too if they contain travel bugs, or geocoins, or some other unique object). Most of my micro's are magnetic, and I'm fairly new at hiding them, but I do attempt to hide them in places of interest.